Electric signaling system.



J. D. TAYLOR.

ELEGTRIO SIGNALING SYSTEM.

APPLICATION FILED APR. 18, 1908.

Patented J an. 6, 1914.

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H H H H H H J 1). TAYLOR.

ELEGTRIO SIGNALING SYSTEM.

APPLIUATION FILED APR.18. 190B.

1 83,306. Patented Jan. 6, 1914.

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COLUMBIA PUNOGRAPH COUWASHINGTONI D C- UNITED STATES PATN T FIQE.

JOHN D. TAYLOR, OF EDGEWOOD PARK, PENNSYLVANIA, ASSIGNOR TO THE UNIONSWITCH & SIGNAL COMPANY, OF SVVISSVALE, PENNSYLVANIA, A CORPORATION OFPENNSYLVANIA.

ELECTRIC SIGNALING SYSTEM.

To all whom it may concern:

Be it known that I, JOHN D. TAYLOR, of Edgewood Park, Allegheny county,Pennsylvania, have invented a new and useful Electric Signaling System,of which the following is a full, clear, and exact description,reference being had to the accompanying drawings, forming part of thisspecification, in which Figure 1 is a view showing diagrammatically oneembodiment of my invention; Fig. 2 is a similar diagram showing thepresence of a train in one of the blocks; Fig. 3 is a side View showingthe manner of increasing the impedance of portions of the track rails;Fig. 4: is a section on the line IVIV of Fig. 3; and Fig. 5 is a detailview of one of the plates or laminae.

This invention has relation to block sig naling systems, moreparticularly designed for use on railroads employing electricpropulsion, and to that class of such systems in which the track railsinstead of being separated into insulated blocks or sections areelectrically continuous for both signaling and propulsion currents. Theterm block and sections as used herein and in the claims, are thereforenot intended to designate actually separated blocks or sections of thetrack, but are used for convenience to designate the portions of thetracks which are between adjacent signals.

The present invention is an improvement upon the apparatus described andclaimed in my Patent No. 882,27 6, and is designed to provide means ofimproved character for increasing the impedance of the rails to the flowof alternating current therein.

When an alternating current flows through a conductor, it meets withimpedance which is a compound of the ohmic resistance of the conductorand a reactance due to the magnetic field surrounding the conductor. Ifthe medium surrounding the conductor is composed of iron, the reactanceand therefore the impedance is very much greater than it would be if thespace were occupied only by air or other non-magnetic substance. vVhenan alternating current flows in a track rail, the current of the centralportion meets with a very large impedance due to the fact that it issurrounded by iron, while the current in the surface portion of the railis impeded to a very Specification of Letters Patent. Application filedApril 18, 1908.

Patented Jan. 6, 1914. Serial No. 427,833;

much less extent because it is not surrounded by iron.

My present invention is designed to provide means of simple andefficient character, whereby as much as possible of the track rails maybe surrounded at certain points with iron for the purpose of increasingthe impedance of those portions of the rails. This iron is preferablylaminated to prevent loss from eddy currents and to prevent the currentwhich should be confined to the rail from leaving it and flowing throughthe surrounding envelop. In a rail equipped in this manner, the onlypart of it in which the current can flow unimpeded is the surfaceportion along the top and one side of the head of the rail with whichthe wheels of the train come in contact. This part is, however, only asmall fraction of the entire perimeter of the rail section, andconsequently the resistance and impedance of the rail is very greatlyincreased, thereby making the block limits of the system moredeterminate, as described in my said patent.

The precise nature of my invention will be best understood by referenceto the accompanying drawing diagrams, in which I have shown oneembodiment thereof, it being premised, however, that various changes maybe made therein by those skilled in the art without departing from thespirit and scope of my invention as defined in the appended claims.

In these drawings, the letter A indicates a generator for supplying thepropulsion current, and which may be either a direct current generatoror an alternator. One terminal of this generator is connected to theusual third rail or trolley wire it, and the other terminal ispreferably connected to a conductor m which connects the two rails ofthe track.

B is an alternating current generator for supplying the signalingcircuit. This generator should be adapted to give a current ofconsiderably higher frequency than the generator which supplies thepropulsion current where that generator is an alternator. The currentfrom the generator 13 is led to the various signaling instruments bymeans ofthe line wires or conductors j, is. C and C designatetransformers whose primaries p, p are connected across the conductors j,is, and whose secondaries s, s are connected across the track rails r,r, at as nearly as maybe the middle point of the blocks which theyrespectively supply. The rails 0 r are electrically continuous for allcurrents. Those portions of these rails at and adjacent to each end ofeach block are provided with means for increasing their impedance, asindicated at g, g. This may be conveniently eifected by adding iron toeach side of the rails between their heads and flanges, this added ironbeing preferably in the form of relatively thin plates or laminae 9having portions which fit between the base and head flanges of the rail,and which also extend around the base flanges and underneath the base ofthe rail. At the opposite side of the rail are a series of plates orlaminae g, which are secured to the plates or laminae g by the bolts 9";The plates or laminae g and the plates or laminae g are secured togetherby means of through-bolts g". The laminae g are preferably at theoutside of the rail, and are made to extend upwardly to within a shortdistance of the top of the rail head so as to surround as much of therail as possible with the iron. This added iron acts to increase theimpedance of the rails by forming a complete magnetic circuit around thecurrent carried by the rails, and in efiect multiplies their impedancemany times. These reinforced sections of the rails are located, asstated, at the ends of the blocks opposite the signals S, S. The relayswhich control these signals are connected across the rails at theextreme ends of the reinforced sections. These relays are designated bythe letters R, R, R, R, etc. They are of a type having two elements, oneenergized from the track circuit, and the other from the line wires j,70. In the arrangement shown the armature elements of the relays areconnected across the track rails, and their field elements are connectedacross the line conductors y', 70. The transformers are connected to therails oppositely, that is to say, the positive terminal of thetransformer C is connected to the same track rail as the negativeterminal of the transformer C. The relays between each two transformersare connected to the line and across the track rails in such sense thatthe current from any transformer except the one intended to operate therelay, will be in the wrong direction to close its contacts, and will,therefore, tend to open its contacts. The arrows in the diagramsindicate the direction of the flow of current at any instant, and thefigures preceded by the plus or minus signs indicate the potentials atthe various points corresponding to the currents indicated by thearrows. These figures are, however, merely hypothetical, being used forthe purpose of illustration only, and may have any values withinreasonable limits. The secondary s of the transformer G will,

at a given instant, produce a potential plus 5, in the illustrationgiven, at its connection with the rail r, tending to cause a current toflow in the direction indicated by the arrow; and it may be assumed thatthe impedance of the rail 1* is such that the fall of potential will befour volts between the point plus 5 and the point plus 1 at theextremity of the reinforced rail section 9. From the point plus 1 to theother extremity of the reinforced section g the potential falls two morevolts to minus 1; thence through therail 1' there is a further drop offour volts to the terminal of the secondary s of the transformer C. Inthe other rail 1", the fall of potential is of equal amount, but in thereverse direction. This supposed case gives a difference of two volts ofpotential, tending to force current through each of the armatures a, aof the relays R, R. The fields f, f of the same relays are energizedfrom the line conductors j, is, and in such direction that the currentstherein coacting With the currents in the armatures derived from thetrack rails will cause the armatures to move and close the contacts 6,e. The end of each of the blocks is similarly equipped, and each signalis controlled by two relays, one at each end of the block, and suppliedby current from a transformer between them and the two relays of eachblock having the contacts controlled thereby in series in the local orsignal cont-rolling circuits.

WVhen a train stands on any part of the track section between a relayand the transformer supplying that relay, current is out off from therelay, and the signal circuit is opened, causing the signal to go todanger. The shunting of each relay will, of course, occur a short timebefore the train reaches that relay, even when it is not between therelay and its transformer; but by reason of the added impedance due tothe iron placed alongside the rails, this distance can be very greatlytween a transformer and the relay, this relay will receive current fromthe next transformer beyond, but, as can easily be traced from thediagram, this current is in the wrong direction to cause a closing ofthe relay contacts, and will have a tendency to open the contacts. Itwill also be readily seen that the middle points of the reinforced railsections will be at the potential zero. Two opposite zero points may,therefore, be joined by a solid conductor if desired without affectingthe signaling current. It is desirable to join these points in thismanner for the purpose of preventing as much as possible the unbalancingof the propulsion current. These connections are indicatedat m, m, m",in Fig. 2.

It will be seen that a of any block will always cause theshort-circuiting of one of the two relays of this shortened. When atrain stands betrain in any portion block, and that since these tworelays have their contacts in series in the signal-controlling circuit,that circuit will be held open and the signal guarding the entrance tothat block will remain at danger so long as the blockis occupied. Inleaving any block, a train before losing control of the last relay ofthat block gains control of the first relay of the succeeding block, andthereby holds the signal behind the train at danger until such time asit is protected by the signal at the entrance to the next block. Themanner in which relays are affected by the presence of a train will beclearly seen from Fig. 2. By reason of the increased impedance of theend portions of the track rails at the block limits, as hereindescribed, the distances at which adjacent relays of two adjacent blockswill be shortcircuited by the train can be very closely determined, sothat there will be but a comparatively small overlapping of the blocks.It will further appear that by the arrangement described it isimpossible for any relay to be operated except by current from thetransformer which is intended to operate it. The arrangement of thecircuit is made very simple, but few line conductors being requiredsince the invention permits the use of single-phase currents for thesignaling circuits.

It will be obvious that many changes may be made in my invention. Thus,changes may be made'in the form of the plates or laminae, and in themanner of securing them in place; relays of any suitable type may beused for controlling the local signal circuits, and the manner ofapplying the signal currents to the track rails may be changed.

I claim 1. In a continuous rail block-signaling system, track railshaving portions of increased impedance consisting of transverse platesor laminae of magnetic material at the sides of and underneath therails; substantially as described.

2. In a continuous rail block-signaling system, a track rail having alaminated body of iron extending at the sides of and underneath the sameat a portion substantially as described.

3. In a continuous rail block-signaling system, means for increasing theimpedance of the track rails, consisting of laminae fitted between thehead and base flanges of the rails, and also extending underneath thebase flanges; substantially as described.

4. In a continuous rail block signaling system, means for increasing theimpedance of the track rails, consisting of laminated iron plates fittedbetween the head and base flanges of the rails at one side thereof, andextending underneath the rail bases, and other plates or laminae at theopposite sides of the rails and secured to the plates or laminae whichextend underneath the rail bases; substantially as described.

5. In a continuous rail block-signaling system, means for increasing theimpedance of portions of the track rails, consisting of laminated ironplates placed at the sides of the rail and underneath the same, theplates at the outer sides of the rails being extended upwardly at thesides of the rail heads; substantially as described.

6. In a continuous rail block-signaling system, means for increasing theimpedance of portions of the track rails, consisting of a body oflaminated iron inclosing the web and base of the rail; substantially asdescribed.

7. In a continuous rail block-signaling system, means for increasing theimpedance of portions of the track rails, consisting of a body oflaminated iron inclosing the web and base of the rail, and extendingupwardly at one side of the head; substantially as described.

8. A signal system comprising a conductive track rail, and bodies oflaminated magnetic material surrounding said rail with the exception ofits head.

In testimony whereof, I have hereunto set my hand.

of its length;

JOHN D. TAYLOR.

Witnesses:

H. M. CoRwIN, GEO. H. PARMELEE.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, D. G.

